An Interview With Aubrey de Grey
Machines Like Us interviews biomedical gerontologist Aubrey de Grey: "It'll almost certainly be a very long time indeed - many decades, possibly centuries - before we can completely repair everything that qualifies as 'damage' [and] therefore totally prevent aging. But luckily, we don't need to reach perfection in order to maintain our youth indefinitely, because a certain amount of damage - the sort of amount we have in early adulthood - is harmless, not causing any disease or debilitation. If we can develop reasonably comprehensive repair and maintenance therapies, that will buy time to develop even more comprehensive ones, thus buying more time to improve the therapies even more, and so on indefinitely, even if the therapies never achieve absolute perfection. "Longevity escape velocity" is the name I've given to the rate at which we would need to maintain this improvement of the therapies, following the initial breakthrough that gives middle-aged people maybe 30 extra years of healthy life."
Link: http://www.machineslikeus.com/cms/MLU-interviews-aubrey-de-grey.html